X-ray topographic investigation of microdeformation of InSb single crystals

Abstract

The dislocation distribution around indentations on ±(001) surfaces of highly perfect InSb single crystals has been studied by X-ray topography. Three types of dislocation loop have been identified. Type-I loops lie in {111} planes and are screw-B(g) or screw–A(g) type with ± ½[110] and ± ½[110] Burgers vectors. They can extend over I mm from the indentation site and penetrate up to 170 μm deep into the crystal. Type-11 dislocations, having the same Burgers vectors as type-I dislocations, are 100–150 μm long, 60°B(g) and A(g) dislocation half-loops reaching a depth of 70 μm and less than 30 μm respectively. These prismatic loops are believed to be introduced ab initio during indentation as well as to result from interaction of the first type of dislocation. Type-III dislocations are loops on {111} planes having their Burgers vectors parallel to these planes in 〈110〉 directions. They penetrate over 230 μm into the crystal and arise from the intersection of inclined type-I loops. The dislocation rosette asymmetry is confirmed to arise from the differing velocities of A(g) and B(g) dislocations.